Aluminum-carbon black thickened grease compositions



' pared from carbon blacks application Serial No. 213,464" disclosesthat a Patented Sept. 22, 1953 UNITED STATES PATENT oF-Fic-EALUMINUM-CARBON BLACK 'rrnq g znnn GREASE COMPQSIIEQNS se lark. N- L5 aRosemary OHalloran,

' signor to Standard il nev l n ni Q imenn a corporation ofJJelaware No'Drawing. Application March 29, 1 951,

" ""SeiialfNo. 218,260:

.5 Claims. (01:

This invention relates to lubricating grease compositions andparticularly to lubricating grease containing carbon black combinedtherein. More particularly the"inventi on relates to aluminum soaplubricating grease compositions containing carbon black combined thereinuseful for lubricating heavy moving parts under conditions of extremepressure, high temperature, and high humidity.

It is known in the art that'lubricating greases having outstanding hightemperature properties and resistance to moisture may be prepared bythickening various lubricating 'oils with carbon black. Theselubricating grease compositions have found outstanding utility in suchindustrial applications as steel mill roller bearing lubricating. In U.S. Patent'NO.'2, l5'3,153 itis shown that superior lubricating greases'maybe preand oil. Copending high temperature blending of carbon blackand soaps results in an im roved grease, particularly with regard tonon-stainingtendencies It is believed that the'carbon' black particlessolidify the oil by entrapping it within or strands of carbon blackparticles. This engroups i.

trapment is very resistant to heat, andcarbgn black greases showvessentially no melting point. However, the carbon black structure. soformed is not as resistant as conventional soap systems to separationby. means of pressure, and it has been found that this effectsa'practical limita tion on the applicability of such greases inindustry.""Particularly ciency observed in the lubrication :dffheavyequipment which operates continuously "under extreme conditions of heatand lead. "It is a widespread practice in industry to provide forassured, continuous lubrication of all the parts of such equipment bythe useof automatic lubjricant dispensers.

, It is essential that the lubricating grease comcarbon black positionsused in automatic idispensers 'have 73. low degree of oil sepa ation.This-is due to the fact that when it becomes, necessary jlto shut downthe equipment thelubricating grease used in the continuousgreasingdispensers i's mainltained immobile under pressure. Ifthe pilcom} ponentof the grease tends to separate gradually under these conditions anundesirablaplug'ging f the e ea e'l res ts... n cessitat n iobera tionaldelay for the purpose of cleaning the continuous greasing equipment."Itha's'been'found that the carbon V bleak ra s 32 3 5 are at adisadvantage "under theseconditi' ns" cius'trial iappiicauon in View Offste'aric. acid, the

qause oftheir tendencyto, separate oil under pr s ure, a dto form p u sof d ar black which block the system.

It has now been found, and forms an object of this invention, that thisdisadvantage of carbon black greases may be obviated by incorperatinginto a carbon black grease a minor amount of an alum num soap of a.Sllbstantially saturated high molecular weight fatty acid. Theincorporation of a small amount of aluminum soap reduces the tendency ofoil separation markedly and enables users of continuous greasingequipment to utilize the desirable high temperature and water resistantcharacteristics of carbon black greases. It is believed that thealuminum soap (a well known gelling agent) holds the oil much morefirmly than does carbon black. Improved performance in this respect isthe particular result of using aluminum soap and incorporating thecarbon black into cooled pre-formed soap -oil gel.

v The use of other soaps, such as sodium, lithium. barium, magnesium,strontium, calcium, etc., with carbon black results only in minorimprovements in oil separation properties under a cooled, pre -formedaluminum soap-oil gel.

Although use'un continuous greasing equipment brings out an outstandingadvantage of the novel greases of invention, it isreadily' recognizedthat these greases have'wide utility in intheir. outstanding propertiesof high temperature resistance, water resistance, lack of oilseparation, and high dropping point "The' novel greases may be preparedusing any of the aluminum soaps of the commonly knowngrease..makingflmaterials such as fish oil acids, beef fat, tallow,oleic acid, stearic acid, hydroxysaturated or unsaturated glyceridesof'the fatty acids, or mixtures of the Iabove. coljiliillldl dlalalurnmum stearate is enitirel Sile i w A unt soap varying between 1f.'5to of'Ith e aluminum 'l0%;may be used depending upon the desiredfinal'consistency. Alhtiht oveif d% willigive very stiff greases whencompounded .with' carbon black.' In order to prepare greases of softconsistency and improved oil separation resistance, only a small amount,that is 1.5% to 3.5% of aluminum soap is required. Mixed soaps, forexample, the

EXAMPLES I TO IX in these examples, the desired amount of dehydratedsoap was added to the total mineral oil charge a West Texas crudedistillate having aluminum soap of a mixture of naphthenic and 5 aViscosity at 210 F of 70 s U S and the fatty aclds such as Napalm are fiswung ture heated above the melting point of the soap genmg afgents anda be employed m place of (250- l F.). The carbon black was added and ggggg 3 ggg j of the invem stirred in at this high temperature and the tion3 23 5 any the amoiphous forms of cap grease allowed to pan cool. Thecooled greases and extreme pressure agents were homogenized g z gig} Egg2 3 35311 gfi gig zigg? to the desired consistency. The finished greasesmg btween 3 t6 30% by weight based on the were subjected to the standardASTM dropping h weight of the total composition may be used. gi i maddmon to an 011 Separatlon 5% to 15% by weight is especially preferred.15

a of a a g 2:; on the ultimate use and properties desired in lower endby a double NO 1 filter paper and gg ggi al on utilized in thepreparation a 506 mesh metal screen. The top of the grease of thegreases of invention may Vary Widely 20 sample was then subjected to 100pound nitrogen depending upon the use to which theresulting ggi g z ggsfsg iggg fi fig gf g ggg i fi gease c0r.npoS1t1on.1S-m be A Inn-16mleludin the oil adsorbed by the pa er) was obeither residual ordistillate, of a paraffmic, naphmvvedfifter a 22 hour ms erio 1 a M rest d thenic or mixed base crude having a viscosity jfj s 1 f L en 8 inthe range from about 50 to 1,000 s. U. s. at 25 we Esme 01 Sepala 210 F.may be used. The viscosity of the min-- EXAMPLES X TO XXII t on F mdepend upon. the degree of In these preparations the dehydrated soapgjgfigfit gfjfij gg gfig i gig gfiiig S was added to the oil aha themixture heated until 1' f the soap was completely dispersed in the oil,that may 8 amp eyed m m rangmgplozn 2% is, to temperatures within therange of from 250 to pltefembly 16% 15% by wglgm based to 400 Thesoap-oil solution was allowed 9 F 3 Welght i the fimshed 5 92 i M tocool to a temperature below the transition l p soaps 0115' temperatureof the aluminum soap generally desuliurized fats, phosphorus compounds,chlc- Scribad in United states gfi 2343 736 rimmed compounds mixturesthese Carbon black was added to the mixture b low fives may be addfad toImpart additional extreme the transition temperature of the soap andexpmpertles to these greases F' Well trezne pressure additives blendedin followed by known 1n the art the preparatmn 01 homogenization. Thesegreases were also tested trerne pressure greases it has been foundusually fo dropping pgint andofl separation properties advantag o to u ea ow a e pH ack o The data on the greases prepared in accorda mixture ohigh and W DH blacks. ance with Examples I-XXII are reported in Theinvention will be more fully illustrated by Table I below. Comparativedata on four comthe following examples. mercially used greases are alsoshown.

Table I CARBON BLACK-SOAP GREASES Soap Carbon Black D Blending P pingOil Se aration, Example 1 Wt Wt. i fi Point, gr iims Type Per- Typo Per-F.

cent cent Lithium l X]? Ca-Pb soap-Ca acetate grease Commercial XP Ca-Pbsoap grease Commercial XP Ca soap grease Commercial XP carbon black-Pbsoap grease not determined.

not determined, grease v e r y heavy.

determined.

pounce XXI contained no extreme pressure agent.

pressure agent comprising a lead soap and sulfurized fatty oil. GreaseAn examination of the data in Table I above clearly points out theadvantage of the inventive concept.

The greases of Examples I through IX were prepared by blending variousamounts of the carbon black into the soap-oil mixture at temperaturesabove the transition temperature of the metal soap. It will be notedthat the high dropping points of the resulting grease compositionsindicate that very satisfactory high temperature performance is to beexpected. However, the degree of oil separation shows that the stabilityof the system is insufficient for the greases to be operable incontinuous greasing equipment and allied uses.

In Examples X through XXII the greases were prepared by adding thecarbon black to the soap-oil system below the transition temperature ofthe soap used. In Examples K through XVII it is shown that the soaps oflithium, sodium, magnesium, calcium, strontium, and barium, commonlyused as grease thickeners, form valuable high temperature greases astheir high dropping points indicate, but do not form a sufiicientlystable system to prevent undesirable oil separation under the conditionsencountered in continuous greasing equipment. In Examples XVIII throughXXII however, both desirable high dropping points and low degrees of oilseparation were obtained, indicating that the aluminum soapcarbon blackgreases prepared in accordance with the inventive concept, areexcellently suited for high temperature uses generally, and are verysatisfactory for use in continuous greasing equipment.

It is also contemplated that the greases of invention may be prepared bya continuous process. Such a process may include the preparation of thealuminum soap solution, drawing off into tanks from which it could bepumped back when cool into the original mixing kettle previously chargedwith carbon black. The finished grease could then be pumped from themixing kettle through a suitable homogenizer to result in a finishedgrease composition.

To summarize briefly, this invention relates to improved carbon blackgrease compositions prepared by a process comprising the steps offorming the aluminum soap of a high molecular weight fatty acid, ormixtures of such soap With other aluminum soaps, dispersing said soap inthe desired mineral oil by heating, allowing the solution to cool to atemperature below the transition temperature of the soap, dispersing inthe soap-oil gel the desired'amount of carbon black, and homogenizingthe composition to the desired consistency. Extreme pressure agents mayor may not be added as desired.

What is claimed is:

1. An improved process for the formation of lubricating greasecompositions containing combined therein carbon black which comprisesthe steps of admixing from 1.5% to 10.0% by weight of an aluminum soapof high molecular weight substantially saturated fatty acid in a mineraloil, heating said mixture to completely disperse said soap in said oil,cooling the dispersion below the transition temperature of said aluminumsoap. blending with said cooled soap-oil solution from 3% to 30% byweight of an amorphous carbon black, and working the resulting blenduntil the desired consistency is obtained.

2. An improved process for the formation of lubricating greasecompositions containing combined therein carbon black which comprisesthe steps of admixing from 1.5% to 3.5% by weight of an aluminum soap ofhigh molecular weight substantially saturated fatty acid in a mineraloil, heating said mixture to completely disperse said soap in said oil,cooling the dispersion below the transition temperature of said aluminumsoap, blending with said cooled soap-oil solution from 5% to 15% byweight of an amorphous carbon black, and working the resulting blenduntil the desired consistency is obtained.

3. A process according to claim 2 wherein the aluminum soap is aluminumstea-rate.

4. A process according to claim 2 wherein 10% of the carbon black isused.

5. An improved process for the formation of lubricating greasecompositions containing combined therein carbon black which comprisesthe steps of admixing from 1.5% to 3.5% by weight of the aluminum soapof a high molecular weight substantially saturated fatty acid in amineral lubricating oil having a viscosity at 210 F. within a range offrom about 50 to 1,000 S. U. S., heating said mixture to completelydisperse said soap in said oil, cooling the dispersion below thetransition temperature of said soap, blending with said cooled soap-oilsolution from 5% to 15% by weight of an amorphous carbon black, addingto the blend from 10% to 20% by weight of an extreme pressure additive,and working the resulting blend until the desired consistency isobtained.

ROSEMARY OI-IALLORAN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,470,965 Woods May 24, 1949 2,480,647 Gurd et a1. Aug. 30,1949 2,487,260 Morway Nov. 8, 1949 2,522,460 Morway et al Sept. 12, 19502,543,741 Zweifel Feb. 27, 1951

1. AN IMPROVED PROCESS FOR THE FORMATION OF LUBRICATING GREASE COMPOSITIONS CONTAINING COMBINED THEREIN CARBON BLACK WHICH COMPRISES THE STEPS OF ADMIXING FROM 1.5% TO 10.0% BY WEIGHT OF AN ALUMINUM SOAP OF HIGH MOLECULAR WEIGHT SUBSTANTIALLY SATURATED FATTY ACID IN A MINERAL OIL, HEATING SAID MIXTURE TO COMPLETELY DISPERSE SAID SOAP IN SAID OIL, COOLING THE DISPERSION BELOW THE TRANSITION TEMPERATURE OF SAID ALUMINUM SOAP, BLENDING WITH SAID COOLED SOAP-OIL SOLUTION FROM 3% TO 30% BY WEIGHT OF AN AMORPHOUS CARBON BLACK, AND WORKING THE RESULTING BLEND UNTIL THE DESIRED CONSISTENCY IS OBTAINED. 